AP Physics 1 Unit Plan-Dynamics (Newton's Laws of Motion)

Unit Title: Kinematics

Course: AP Physics 1
Duration: 2 weeks

Unit Objectives

By the end of this unit, students should be able to:

1. Apply Newton's three laws of motion to analyze and solve problems involving forces and motion.
2. Construct free-body diagrams and use them to analyze forces acting on an object.
3. Solve problems involving friction, tension, normal force, and inclined planes.
4. Understand and apply the concept of net force and its relationship to acceleration.
5. Analyze systems of objects (e.g., Atwood machines) using Newton's laws.

Essential Questions

1. How do forces affect the motion of an object?
2. What is the relationship between net force, mass, and acceleration?
3. How can free-body diagrams help us analyze real-world situations?
4. How do friction and other forces influence motion?

Key Concepts

• Newton's First Law (Law of Inertia)
• Newton's Second Law ($F_{\text{net}}=ma$)
• Newton's Third Law (Action-Reaction Pairs)
• Free-body diagrams
• Types of forces: gravitational, normal, frictional, tension, applied
• Static and kinetic friction
• Inclined planes
• Systems of objects (e.g., Atwood machines, connected objects)

Lesson Breakdown

Lesson 1: Introduction to Newton's Laws

• Objective: Understand Newton's First and Second Laws.
• Activities:
  • Engage students with a discussion on everyday examples of forces (e.g., why a car stops when brakes are applied).
  • Introduce Newton's First Law (inertia) and Second Law ($F_{\text{net}}=ma$).
  • Demonstration: Use a dynamics cart and a spring scale to show the relationship between force, mass, and acceleration.
  • Practice problems: Simple calculations using $F_{\text{net}}=ma$.
• Homework: Read textbook section on Newton's Laws and complete basic practice problems.

Lesson 2: Free-Body Diagrams

• Objective: Construct and interpret free-body diagrams.
• Activities:
  • Teach the steps to draw free-body diagrams.
  • Examples: Objects at rest, objects in motion, and objects on inclined planes.
  • Group activity: Students work in pairs to draw free-body diagrams for various scenarios.
• Homework: Assign free-body diagram practice problems.

Lesson 3: Newton's Third Law

• Objective: Understand action-reaction force pairs.
• Activities:
  • Demonstration: Use two spring scales to show equal and opposite forces.
  • Discuss common misconceptions (e.g., "If forces are equal and opposite, why does anything move?").
  • Practice problems: Identify action-reaction pairs in different scenarios.
• Homework: Write a short reflection on how Newton's Third Law applies to a real-world situation (e.g., walking, rowing a boat).

Lesson 4: Friction

• Objective: Analyze the effects of static and kinetic friction.
• Activities:
  • Introduce the equations for friction: $f_s\le {\mu }_{s}N$ and $f_k={\mu }_{k}N$.
  • Lab activity: Measure coefficients of friction using a block and a force sensor.
  • Practice problems: Calculate frictional forces in various scenarios.
• Homework: Assign friction-related problems.

Lesson 5: Inclined Planes

• Objective: Solve problems involving forces on inclined planes.
• Activities:
  • Teach how to resolve forces into components parallel and perpendicular to the incline.
  • Example problems: Objects sliding down an incline, objects at rest on an incline.
  • Group activity: Students solve inclined plane problems on whiteboards.
• Homework: Assign inclined plane problems.

Lesson 6: Systems of Objects

• Objective: Analyze systems of objects using Newton's Laws.
• Activities:
  • Teach how to analyze Atwood machines and connected objects.
  • Example problems: Two masses connected by a string over a pulley.
  • Group activity: Solve multi-object problems.
• Homework: Assign Atwood machine problems.

Lesson 7: Review and Practice

• Objective: Reinforce understanding of Newton's Laws through problem-solving.
• Activities:
  • Review key concepts with a class discussion.
  • Practice AP-style multiple-choice and free-response questions.
  • Group quiz: Students work in teams to solve challenging problems.
• Homework: Complete a review worksheet.

Lesson 8: Assessment

• Objective: Assess understanding of Newton's Laws.
• Activities:
  • Unit test: Include multiple-choice and free-response questions similar to AP exam format.
  • Example topics:
    • Free-body diagrams
    • Friction and inclined planes
    • Systems of objects
    • Conceptual questions about Newton's Laws